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Photoinduced optical anisotropy in azobenzene methacrylate block copolymers: Influence of molecular weight and irradiation conditions. / Gimeno, Sofia; Forcen, Patricia; Oriol, Luis; Piñol, Milagros; Sanchez, Carlos; Rodriguez, Francisco J.; Alcala, Rafael; Jankova Atanasova, Katja; Hvilsted, Søren.

In: European Polymer Journal, Vol. 45, No. 1, 2009, p. 262-271.

Publication: Research - peer-reviewJournal article – Annual report year: 2009

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Gimeno, Sofia; Forcen, Patricia; Oriol, Luis; Piñol, Milagros; Sanchez, Carlos; Rodriguez, Francisco J.; Alcala, Rafael; Jankova Atanasova, Katja; Hvilsted, Søren / Photoinduced optical anisotropy in azobenzene methacrylate block copolymers: Influence of molecular weight and irradiation conditions.

In: European Polymer Journal, Vol. 45, No. 1, 2009, p. 262-271.

Publication: Research - peer-reviewJournal article – Annual report year: 2009

Bibtex

@article{402dc7e20abe4694a0f9356171357f84,
title = "Photoinduced optical anisotropy in azobenzene methacrylate block copolymers: Influence of molecular weight and irradiation conditions",
keywords = "Photoaddressable polymers, Birefringence, Optical storage, Block copolymers, Azobenzene, Phase segregation",
publisher = "Pergamon",
author = "Sofia Gimeno and Patricia Forcen and Luis Oriol and Milagros Piñol and Carlos Sanchez and Rodriguez, {Francisco J.} and Rafael Alcala and {Jankova Atanasova}, Katja and Søren Hvilsted",
year = "2009",
doi = "10.1016/j.eurpolymj.2008.10.034",
volume = "45",
number = "1",
pages = "262--271",
journal = "European Polymer Journal",
issn = "0014-3057",

}

RIS

TY - JOUR

T1 - Photoinduced optical anisotropy in azobenzene methacrylate block copolymers: Influence of molecular weight and irradiation conditions

A1 - Gimeno,Sofia

A1 - Forcen,Patricia

A1 - Oriol,Luis

A1 - Piñol,Milagros

A1 - Sanchez,Carlos

A1 - Rodriguez,Francisco J.

A1 - Alcala,Rafael

A1 - Jankova Atanasova,Katja

A1 - Hvilsted,Søren

AU - Gimeno,Sofia

AU - Forcen,Patricia

AU - Oriol,Luis

AU - Piñol,Milagros

AU - Sanchez,Carlos

AU - Rodriguez,Francisco J.

AU - Alcala,Rafael

AU - Jankova Atanasova,Katja

AU - Hvilsted,Søren

PB - Pergamon

PY - 2009

Y1 - 2009

N2 - The photoinduced anisotropy in a series of azomethacrylate block copolymers with different Molecular weights and azo contents has been investigated under several irradiation conditions. Depending on molecular weight and composition, different microstructures (disordered, lamellar, spherical) appear, due to block microsegregation. Measurements of birefringence (Delta n) induced with linearly polarised 488 nm light show that the highest (and stable) Delta n(N) values (birefringence normalised to the azo content) are achieved in copolymers with a lamellar structure. Lower Delta n(N) are obtained in the copolymers in which azobenzene units segregate to nano spheres and the lowest (and less stable) Delta n(N) values, appear in disordered systems not showing any defined microstructure. Besides, higher Delta n(N) is obtained in the copolymers with larger molecular weight of the poly (methyl methacrylate) and the azo polymer blocks, both in the microspheres segregated polymers as well as in those without a clear microstructure. This behaviour is consistent with that of the photoinduced order of azobenzene units obtained from dichroism measurements. Irradiation temperature (from 30 to 90 degrees C) and light power (from 100 to 500 mW/cm(2)) also influence the photoinduced response. Photoinduced Delta n(N) growth rate is faster when both temperature and irradiation power increase. Furthermore, birefringence is only induced at temperatures up to 90 degrees C, the maximum value being obtained at about 70 degrees C. No clear dependence of the final Delta n(N) value with light power has been found.

AB - The photoinduced anisotropy in a series of azomethacrylate block copolymers with different Molecular weights and azo contents has been investigated under several irradiation conditions. Depending on molecular weight and composition, different microstructures (disordered, lamellar, spherical) appear, due to block microsegregation. Measurements of birefringence (Delta n) induced with linearly polarised 488 nm light show that the highest (and stable) Delta n(N) values (birefringence normalised to the azo content) are achieved in copolymers with a lamellar structure. Lower Delta n(N) are obtained in the copolymers in which azobenzene units segregate to nano spheres and the lowest (and less stable) Delta n(N) values, appear in disordered systems not showing any defined microstructure. Besides, higher Delta n(N) is obtained in the copolymers with larger molecular weight of the poly (methyl methacrylate) and the azo polymer blocks, both in the microspheres segregated polymers as well as in those without a clear microstructure. This behaviour is consistent with that of the photoinduced order of azobenzene units obtained from dichroism measurements. Irradiation temperature (from 30 to 90 degrees C) and light power (from 100 to 500 mW/cm(2)) also influence the photoinduced response. Photoinduced Delta n(N) growth rate is faster when both temperature and irradiation power increase. Furthermore, birefringence is only induced at temperatures up to 90 degrees C, the maximum value being obtained at about 70 degrees C. No clear dependence of the final Delta n(N) value with light power has been found.

KW - Photoaddressable polymers

KW - Birefringence

KW - Optical storage

KW - Block copolymers

KW - Azobenzene

KW - Phase segregation

U2 - 10.1016/j.eurpolymj.2008.10.034

DO - 10.1016/j.eurpolymj.2008.10.034

JO - European Polymer Journal

JF - European Polymer Journal

SN - 0014-3057

IS - 1

VL - 45

SP - 262

EP - 271

ER -